Amino acid complexes and the use thereof in producing olefin polymers

ABSTRACT

An amino acid complex of the formula I, 
                 
 
where M is selected from among Fe, Co, Ni, Pd, Pt and Ir, preferably Ni, can be used for the polymerization of olefins.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to amino acid complexes of the formula I,where the variables are defined as follows:

-   M is selected from among Fe, Co, Ni, Pd, Pt and Ir,-   X is selected from among O and S;-   R¹ and R² are identical or different and are each selected from    among    -   hydrogen,    -   C₁-C₈-alkyl, substituted or unsubstituted,    -   C₃-C₁₂-cycloalkyl, substituted or unsubstituted,    -   C₇-C₁₃-aralkyl,    -   C₆-C₁₄-aryl, unsubstituted or substituted by one or more        identical or different substituents selected from among    -   C₁-C₈-alkyl, substituted or unsubstituted,    -   C₃-C₁₂-cycloalkyl,    -   C₇-C₁₃-aralkyl,    -   C₆-C₁₄-aryl,    -   halogen,    -   C₁-C₆-alkoxy,    -   C₆-C₁₄-aryloxy,    -   SiR⁴R⁵R⁶ and O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected from among        C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and C₆-C₁₄-aryl;    -   five- to six-membered nitrogen-containing heteroaryl radicals Y,        unsubstituted or substituted by one or more identical or        different substituents selected from among    -   C₁-C₈-alkyl, substituted or unsubstituted,    -   C₃-C₁₂-cycloalkyl,    -   C₇-C₁₃-aralkyl,    -   C₆-C₁₄-aryl,    -   halogen,    -   C₁-C₆-alkoxy,    -   C₆-C₁₄-aryloxy,    -   SiR⁴R⁵R⁶ and O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected from among        C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and C₆-C₁₄-aryl,    -   and CH₂—Y, where Y is as defined above;-   y is an integer from 0 to 4;-   L¹ is an uncharged, inorganic or organic ligand;-   L² is an inorganic or organic anionic ligand, where L¹ and L² may be    joined to one another by one or more covalent bonds;-   z is an integer from 0 to 3;-   x is an integer from 0 to 3.

Furthermore, the present invention relates to a process for preparingthe novel amino acid complexes of the formula I and to catalyst systemsfor the polymerization or copolymerization of olefins, comprising one ormore amino acid complexes of the formula I and, if desired, anactivator, and also to a process for the polymerization orcopolymerization of olefins using the catalyst system of the presentinvention.

2. Description of the Background

Polymers and copolymers of olefins are of great economic importancebecause the monomers are readily available in large quantities andbecause the polymers can be varied within a wide range by variation ofthe production process or the processing parameters. In the productionprocess, particular attention has to be paid to the catalyst used.

The systems described in the literature are not free of disadvantages.Thus, the cyclopentadienyl ligands of most metallocenes requirecomplicated syntheses which can take 4 or more hours, for example asdescribed in H.-H. Brintzinger et al., Angew. Chem. 1995, 107, 1255, inEP-A 0 549 900 or EP-A 0 576 970. However, multistage syntheses make thecatalysts more expensive.

The systems disclosed in WO 96/23010 give, after activation withmethylaluminoxane (“MAO”), highly branched polymers which, however, donot have a sufficiently high molecular weight for numerous materialsapplications.

The complexes described by Brookhart and Gibson (e.g. WO 98/27124) aresimple to obtain in terms of the synthesis, but they only incorporatecomonomers in very small amounts. The polymerization of ethylene, forexample, gives highly linear, brittle polymers having a limitedsuitability as materials. K. Severin et al., Chem. Ber. 1995, 128, 1127,disclose Rh complexes of the formula A

where R=methyl or benzyl, which can readily be synthesized from thenatural amino acids. They are suitable as chiral catalysts forhydrogenation, as cytostatics or as labeling reagents in biochemistry.However, they are unsuitable as polymerization catalysts.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide

-   -   novel complexes which are polymerization-active toward olefins,        whose ligands can be obtained by simple syntheses or are        commercially available and which give high molecular weight        polyethylene;    -   catalyst systems for the polymerization or copolymerization of        olefins, comprising the novel complexes and suitable activators,    -   a process for the polymerization or copolymerization of olefins        using these catalyst systems,    -   a process for preparing the complexes,    -   a solid catalyst which is suitable for gas-phase polymerization,        suspension polymerization or bulk polymerization and comprises a        complex, a suitable activator and a solid support,    -   a process for preparing a solid catalyst from the novel        complexes, and    -   to use these for the polymerization or copolymerization of        olefins.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

We have found that this object is achieved by the amino acid complexesdefined at the outset.

In formula I

-   M is selected from among elements of groups 6 to 10 of the Periodic    Table of the Elements, for example Fe, Co, Ni, Pd, Pt or Ir,    preferably Ni or Pd and particularly preferably Ni;-   X is selected from among oxygen and sulfur; preference is given to    oxygen;-   R¹ to R³ are identical or different and are selected from among    -   hydrogen;    -   C₁-C₈-alkyl groups such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably        C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,        isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, particularly preferably C₁-C₄-alkyl such as        methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl        and tert-butyl;    -   examples of substituted C₁-C₈-alkyl groups are: monohalogenated        or polyhalogenated C₁-C₈-alkyl groups such as fluoromethyl,        difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,        trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl,        pentafluoroethyl, perfluoropropyl and perfluorobutyl,        particularly preferably fluoromethyl, difluoromethyl,        trifluoromethyl and perfluorobutyl;    -   C₁-C₈-alkyl groups substituted by one or more functional groups        such as amino groups, hydroxyl groups, thioether groups, thiol        groups, carboxyl groups or guanidine groups; particular        preference is given to the following functionalized alkyl        groups:        -   —CH₂—CH₂—CH₂—CH₂—NH₂, —CH(OH)—CH₃, —CH₂—OH,            —CH₂—CH₂—CH(OH)—CH₂—NH₂, —CH₂—CH₂—SCH₃, —CH₂—CONH₂;        -   —CH₂—CH₂—COOH, —CH₂—CH₂—CONH₂; —CH₂—COOH,            —CH₂—CH₂—NH—C(NH₂)₂;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl and cyclododecyl; preferably cyclopentyl,        cyclohexyl and cycloheptyl;    -   examples of substituted cycloalkyl groups are:        2-methylcyclopentyl, 3-methylcyclopentyl,        cis-2,4-dimethylcyclopentyl, trans-2,4-dimethylcyclopentyl,        cis-2,5-dimethylcyclopentyl, trans-2,5-dimethylcyclopentyl,        2,2,5,5-tetramethylcyclopentyl, 2-methylcyclohexyl,        3-methylcyclohexyl, 4-methylcyclohexyl,        cis-2,6-dimethylcyclohexyl, trans-2,6-dimethylcyclohexyl,        cis-2,6-diisopropylcyclohexyl, trans-2,6-diisopropylcyclohexyl,        2,2,6,6-tetramethylcyclohexyl, 2-methoxycyclopentyl,        2-methoxycyclohexyl, 3-methoxycyclopentyl, 3-methoxycyclohexyl,        2-chlorocyclopentyl, 3-chlorocyclopentyl,        2,4-dichlorocyclopentyl, 2,2,4,4-tetrachlorocyclopentyl,        2-chlorocyclohexyl, 3-chlorocyclohexyl, 4-chlorocyclohexyl,        2,5-dichlorocyclohexyl, 2,2,6,6-tetrachlorocyclohexyl,        2-thiomethylcyclopentyl, 2-thiomethylcyclohexyl,        3-thiomethylcyclopentyl, 3-thiomethylcyclohexyl and further        derivatives;    -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,        2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly        preferably benzyl;    -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,        1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably        phenyl, 1-naphthyl and 2-naphthyl, particularly preferably        phenyl;    -   C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,        2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl substituted by        one or more identical or different substituents selected from        among    -   C₁-C₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably        C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,        isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, particularly preferably C₁-C₄-alkyl such as        methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl        and tert-butyl;    -   examples of substituted C₁-C₈-alkyl groups are: monohalogenated        or polyhalogenated C₁-C₈-alkyl groups such as fluoromethyl,        difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,        trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl,        pentafluoroethyl, perfluoropropyl and perfluorobutyl,        particularly preferably fluoromethyl, difluoromethyl,        trifluoromethyl and perfluorobutyl;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl and cyclododecyl; preferably cyclopentyl,        cyclohexyl and cycloheptyl;    -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,        2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly        preferably benzyl;    -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,        1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably        phenyl, 1-naphthyl and 2-naphthyl, particularly preferably        phenyl;    -   halogen, for example fluorine, chlorine, bromine and iodine,        particularly preferably fluorine and chlorine;    -   C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,        isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy,        n-pentoxy, isopentoxy, n-hexoxy and isohexoxy, particularly        preferably methoxy, ethoxy, n-propoxy and n-butoxy;    -   C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,        meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and        9-anthryloxy;    -   silyl groups SiR⁴R⁵R⁶, where R⁴-R⁶ are selected independently        from among hydrogen, C₁-C₈-alkyl groups, the benzyl group and        C₆-C₁₄-aryl group; preference is given to the trimethylsilyl,        triethylsilyl, triisopropylsilyl, diethylisopropylsilyl,        dimethylhexylsilyl, tert-butyldimethylsilyl,        tert-butyldiphenylsilyl, tribenzylsilyl, triphenylsilyl and        tri-para-xylylsilyl groups; particular preference is given to        the trimethylsilyl group and the tert-butyldimethylsilyl group;    -   silyloxy groups O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected        independently from among hydrogen, C₁-C₈-alkyl groups, the        benzyl group and C₆-C₁₄-aryl group; preference is given to the        trimethylsilyloxy, triethylsilyloxy, triisopropylsilyloxy,        diethylisopropylsilyloxy, dimethylhexylsilyloxy,        tert-butyldimethylsilyloxy, tert-butyldiphenylsilyloxy,        tribenzylsilyloxy, triphenylsilyloxy and tri-para-xylylsilyloxy        groups; particular preference is given to the trimethylsilyloxy        group and the tert-butyldimethylsilyloxy group;    -   five- to six-membered nitrogen-containing heteroaryl radicals        such as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,        2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2,4-triazol-3-yl,        1,2,4-triazol-4-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl,        3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,        5-pyrimidinyl, N-indolyl, 2-indolyl, 3-indolyl and N-carbazolyl;    -   five- to six-membered nitrogen-containing heteroaryl radicals        such as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,        2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2,4-triazol-3-yl,        1,2,4-triazol-4-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl,        3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,        5-pyrimidinyl, N-indolyl, 2-indolyl, 3-indolyl and N-carbazolyl        substituted by one or more identical or different substituents        selected from among    -   C₁-C₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably        C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,        isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, particularly preferably C₁-C₄-alkyl such as        methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl        and tert-butyl;    -   examples of substituted C₁-C₈-alkyl groups are: monohalogenated        or polyhalogenated C₁-C₈-alkyl groups such as fluoromethyl,        difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,        trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl,        pentafluoroethyl, perfluoropropyl and perfluorobutyl,        particularly preferably fluoromethyl, difluoromethyl,        trifluoromethyl and perfluorobutyl;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl and cyclododecyl; preferably cyclopentyl,        cyclohexyl and cycloheptyl;    -   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,        2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly        preferably benzyl;    -   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,        1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably        phenyl, 1-naphthyl and 2-naphthyl, particularly preferably        phenyl;    -   halogen, for example fluorine, chlorine, bromine and iodine,        particularly preferably fluorine and chlorine;    -   C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,        isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy,        n-pentoxy, isopentoxy, n-hexoxy and isohexoxy, particularly        preferably methoxy, ethoxy, n-propoxy and n-butoxy;    -   C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,        meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and        9-anthryloxy;    -   silyl groups SiR⁴R⁵R⁶, where R⁴-R⁶ are selected independently        from among hydrogen, C₁-C₈-alkyl groups, the benzyl group and        C₆-C₁₄-aryl group; preference is given to the trimethylsilyl,        triethylsilyl, triisopropylsilyl, diethylisopropylsilyl,        dimethylhexylsilyl, tert-butyldimethylsilyl,        tert-butyldiphenylsilyl, tribenzylsilyl, triphenylsilyl and        tri-para-xylylsilyl groups; particular preference is given to        the trimethylsilyl group and the tert-butyldimethylsilyl group;    -   silyloxy groups O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected        independently from among hydrogen, C₁-C₈-alkyl groups, the        benzyl group and C₆-C₁₄-aryl group; preference is given to the        trimethylsilyloxy, triethylsilyloxy, triisopropylsilyloxy,        diethylisopropylsilyloxy, dimethylhexylsilyloxy,        tert-butyldimethylsilyloxy, tert-butyldiphenylsilyloxy,        tribenzylsilyloxy, triphenylsilyloxy and tri-para-xylylsilyloxy        groups; particular preference is given to the trimethylsilyloxy        group and the tert-butyldimethylsilyloxy group;        or R¹ to R³ may be C₁-C₈-alkyl substituted by a 5- to 6-membered        heteroaromatic Y, preferably methyl substituted by a 5- to        6-membered heteroaromatic, for example 3-indolylmethyl or        5-imidazolylmethyl.

In a preferred embodiment, two adjacent radicals R¹ to R³ are covalentlybound to one another and form a 5- to 10-membered ring. Thus, forexample, R¹ and R² may together be: —(CH₂)₃-(trimethylene),—(CH₂)₄-(tetramethylene), —(CH₂)₅-(pentamethylene),—(CH₂)₆-(hexamethylene), —CH₂—CH═CH—, —CH₂—CH═CH—CH₂—, —CH═CH—CH═CH—,—O—CH₂—O—, —O—CHMe—O—, —O—CH—(C₆H₅)—O—, —O—CH₂—CH₂—O—, —O—CMe₂—O—,—NMe—CH₂—CH₂—NMe—, —NMe—CH₂—NMe— or —O—SiMe₂—O— where Me=CH₃. In apreferred example, R¹ and R² together form a trimethylene unit which mayin turn bear one or more C₁-C₈-alkyl or hydroxyl groups as substituents,where C₁-C₈-alkyl is as defined above.

-   y is an integer from 0 to 4, particularly preferably 0.-   L¹ are identical or different and are selected from among uncharged,    inorganic or organic ligands, for example from among phosphines of    the formula (R⁷)_(x)PH_(3−x) and amines of the formula    (R⁷)_(x)NH_(3−x), where x is an integer from 0 to 3. However, ethers    (R⁷)₂O such as dialkyl ethers, e.g. diethyl ether, or cyclic ethers,    for example tetrahydrofuran, H₂O, alcohols (R⁷)OH such as methanol    or ethanol, pyridine, pyridine derivatives of the formula    C₅H_(5−x)(R⁷)_(x)N, for example 2-picoline, 3-picoline, 4-picoline,    2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine or    3,5-lutidine, CO, C₁-C₁₂-alkyl nitriles or C₆-C₁₄-aryl nitriles,    e.g. acetonitrile, propionitrile, butyronitrile or benzonitrile, are    also suitable. Further ligands which can be employed are singly or    multiply ethylenically unsaturated double bond systems such as    ethenyl, propenyl, cis-2-butenyl, trans-2-butenyl, cyclohexenyl or    norbornenyl.-   L² is selected from among inorganic and organic anionic ligands, for    example from among    -   halide ions such as fluoride, chloride, bromide and iodide,        preferably chloride and bromide,    -   amide anions (R⁷)_(h)NH_(2−h), where h is an integer from 0 to        2,    -   C₁-C₆-alkyl anions such as (CH₃)⁻, (C₂H₅)⁻, (C₃H₇)—,        (n-C₄H₉)^(−, (tert-C) ₄H₉)⁻ and (C₆H₁₄)⁻;    -   the allyl anion and the methallyl anion,    -   the benzyl anion and    -   C₆-C₁₄-aryl anions such as (C₆H₅)⁻.

Here, the radicals R⁷ are identical or different and are selectedindependently from among

-   hydrogen,-   C₁-C₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,    n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,    sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,    isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably    C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,    isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,    neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,    sec-hexyl, particularly preferably C₁-C₄-alkyl such as methyl,    ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and    tert-butyl;-   the benzyl group and-   C₆-C₁₄-aryl groups, such as phenyl, 1-naphthyl, 2-naphthyl,    1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,    3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl,    1-naphthyl and 2-naphthyl, particularly preferably phenyl;-   C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,    2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,    4-phenanthryl and 9-phenanthryl substituted by one or more identical    or different substituents selected from among-   C₁-C₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,    n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,    sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,    isohexyl, sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably    C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,    isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,    neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,    sec-hexyl, particularly preferably C₁-C₄-alkyl such as methyl,    ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and    tert-butyl;-   examples of substituted C₁-C₈-alkyl groups are: monohalogenated or    polyhalogenated C₁-C₈-alkyl groups such as fluoromethyl,    difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,    trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl,    pentafluoroethyl, perfluoropropyl and perfluorobutyl, particularly    preferably fluoromethyl, difluoromethyl, trifluoromethyl and    perfluorobutyl;-   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,    cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,    cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl    and cycloheptyl;-   C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,    1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,    3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,    2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly    preferably benzyl;-   C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,    2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,    4-phenanthryl and 9-phenanthryl, preferably phenyl, 1-naphthyl and    2-naphthyl, particularly preferably phenyl;-   halogen, such as fluorine, chlorine, bromine and iodine,    particularly preferably fluorine and chlorine;-   C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy,    n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy,    n-hexoxy and isohexoxy, particularly preferably methoxy, ethoxy,    n-propoxy and n-butoxy;-   C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,    meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and    9-anthryloxy;-   silyl groups SiR⁴R⁵R⁶, where R⁴-R⁶ are selected independently from    among hydrogen, C₁-C₈-alkyl groups, the benzyl group and C₆-C₁₄-aryl    group; preference is given to the trimethylsilyl, triethylsilyl,    triisopropylsilyl, diethylisopropylsilyl, dimethylhexylsilyl,    tert-butyldimethylsilyl, tert-butyldiphenylsilyl, tribenzylsilyl,    triphenylsilyl and tri-para-xylylsilyl groups; particular preference    is given to the trimethylsilyl group and the tert-butyldimethylsilyl    group;-   silyloxy groups O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected independently    from among hydrogen, C₁-C₈-alkyl groups, the benzyl group and    C₆-C₁₄-aryl group; preference is given to the trimethylsilyloxy,    triethylsilyloxy, triisopropylsilyloxy, diethylisopropylsilyloxy,    dimethylhexylsilyloxy, tert-butyldimethylsilyloxy,    tert-butyldiphenylsilyloxy, tribenzylsilyloxy, triphenylsilyloxy and    tri-para-xylylsilyloxy groups; particular preference is given to the    trimethylsilyloxy group and the tert-butyldimethylsilyloxy group;-   z is an integer from 1 to 3;-   x is an integer from 0 to 3.

In a particular embodiment, L¹ and L² are joined to one another by oneor more covalent bonds. Examples of such ligands are 1,5-cyclooctadienylligands (“COD”), 1,6-cyclodecenyl ligands and1,5,9-all-trans-cyclododecatrienyl ligands.

In a further preferred embodiment, L¹ is tetramethylethylenediamine,with only one nitrogen coordinating to the nickel.

When R¹ is H, the stereochemistry on the carbon atom bearing R¹ can becontrolled by the choice of amino acid. L-Amino acids are generally morereadily available and for this reason the L configuration on the carbonatom bearing R¹ is preferred.

The novel amino acid complexes of the formula I are advantageouslyprepared by deprotonation of an amino acid of the formula II,

where the variables are as defined above, by means of a strong base,followed by reaction with a suitable metal compound of the formulaM(L¹)_(z+1)L²X¹, where

-   -   X¹ is selected from among halides such as fluoride, chloride,        bromide and iodide, preferably fluoride and bromide, and        C₁-C₄-alkoxides such as methoxide, ethoxide and tert-butoxide,        and the other variables are as defined above.

Suitable bases are the bases customary in transition metal chemistry,for example lithium diisopropylamide “LDA”, alkyllithium compounds suchas methyllithium and n-butyllithium and also alkoxides such as sodiummethoxide, potassium methoxide, sodium ethoxide, potassium ethoxide,sodium isopropoxide or potassium tert-butoxide, with preference beinggiven to alkoxides. These alkoxides are usually used as a solution inthe corresponding alcohol, but can also be used as solids. For thedeprotonation of the amino acids of the formula II, the solutions of thealkoxides can be used in freshly prepared form or as commerciallyavailable solutions. Preference is given to using freshly preparedalkoxide solutions whose concentration is usually determined bytitration.

The reaction conditions for the deprotonation are generally notcritical; preference is given to reaction temperatures of from −20° C.to +80° C. and reaction times of from 1 to 60 minutes. To overcome thesometimes very low solubility of the amino acids of the formula II, itis necessary to disperse the amino acids well, for which vigorousstirring and use of ultrasound have been found to be useful.

The molar ratio of base to amino acid can be selected within certainlimits, with a molar ratio of from 1.1:1 to 1:1.1 having been found tobe preferred and equimolar amounts having been found to be particularlypreferred.

The deprotonated amino acids can be isolated and stored for a number ofmonths, although attention has to be paid to exclusion of moistureduring storage. However, in a preferred embodiment of the process of thepresent invention, the deprotonated amino acid is not isolated and isprocessed further in situ.

The deprotonated amino acid is reacted with a metal compound of theformula M(L¹)_(z+1)L²X¹. The reaction conditions for the reaction aregenerally not critical. Preference is given to reaction temperatures offrom −20° C. to +80° C. and reaction times of from 1minute to 10 hours,particularly preferably from 1 to 5 hours. The order of addition of thereagents can be chosen freely. The molar ratio of metal compound todeprotonated amino acid can be selected within certain limits, withequimolar amounts having been found to be particularly preferred.

The preparation of suitable metal compounds is known in principle;methods of preparation may be found, for example, in S. Y. Desjardins etal., J. Organomet. Chem. 1996, 515, 233.

The reaction mixtures are worked up by the operations customary incoordination chemistry, e.g. crystallization, filtration, precipitation,centrifugation or chromatography, preferably using heatable/coolablecolumns. When selecting purification methods, attention should be paidto ensuring that the equivalent of the ligand L¹ split off during thepreparation of the novel amino acid complexes of the formula I isremoved essentially quantitatively. Removal of salts of X¹ formed duringthe synthesis, for example LiX¹, NaX¹ or KX¹ depending on the base used,is advantageous.

The novel amino acid complexes of the formula I are in many casesobtained as isomer mixtures. Separation of the isomers is possible insome cases. However, it is not necessary to separate the isomers for usein polymerization.

For the complexes of the formula I to be polymerization-active, they canbe activated using an activator, which may also be referred to ascocatalyst. The use of an activator is the preferred embodiment of thepresent invention.

Suitable cocatalysts are aluminum alkyls of the formula Al(R^(k))₃,lithium alkyls of the formula LiR^(k) and aluminoxanes, with particularpreference being given to aluminum alkyls of the formula Al(R^(k))₃ andaluminoxanes.

In these compounds, the radicals R^(k) are identical or different andare each C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl;preferably C₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, particularly preferably C₁-C₄-alkyl such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

The structure of the aluminoxanes is not known precisely. They areproducts obtained by careful partial hydrolysis of aluminum alkyls (cf.DE-A 30 07 725). These products are not pure structurally uniformcompounds but mixtures of open-chain and cyclic structures of the typesIIIa and b.

In the formulae IIIa and b

the radicals R^(m) are identical or different and are each,independently of one another,

-   -   C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl, isopropyl,        n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,        sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,        isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl,        n-decyl, or n-dodecyl; preferably C₁-C₆-alkyl such as methyl,        ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,        tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl,        1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,        particularly preferably methyl;    -   C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,        cycloundecyl or cyclododecyl; preferably cyclopentyl, cyclohexyl        or cycloheptyl;    -   C₇-C₂₀-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,        1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,        3-phenylpropyl, 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl or        4-phenylbutyl, particularly preferably benzyl, or    -   C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,        2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,        3-phenanthryl, 4-phenanthryl or 9-phenanthryl, preferably        phenyl, 1-naphthyl or 2-naphthyl, particularly preferably        phenyl; and    -   n is an integer from 0 to 40, preferably from 0 to 25 and        particularly preferably from 0 to 22.

Cage-like structures for aluminoxanes are also discussed in theliterature (Y. Koide, S. G. Bott, A. R. Barron Organometallics 1996, 15,2213-26; A. R. Barron Macromol. Symp. 1995, 97, 15). Regardless of theactual structure of the aluminoxanes, they are suitable as scavengeralkyls and as cocatalysts for the novel complexes of the formula I.Aluminoxanes are added in significant molar excesses. Thus, a molarratio M:Al of from 1:5 to 1:5000, preferably from 1:10 to 1:1000 andparticularly preferably from 1:50 to 1:500, is chosen.

It is also possible to use mixtures of two or more aluminum alkyls orlithium alkyls as cocatalyst and scavenger alkyl. Mixtures of aluminumalkyls with lithium alkyls are also suitable.

Mixtures of various aluminoxanes are particularly preferred activatorsin cases where the polymerization is carried out in solution in aparaffin, for example n-heptane or isododecane. A particularly preferredmixture is the CoMAO of the formula [(CH₃)_(0.9)(iso-C₄H₉)_(0.1)AlO]_(n)which is commercially available from Witco GmbH.

According to present conceptions, suitable activators for amino acidcomplexes of the formula I abstract a ligand L¹ or L². In place ofaluminoxanes of the formula IIIa or b or the above-described aluminum orboron compounds bearing electron-withdrawing radicals, the activator canbe, for example, an olefin complex of rhodium or nickel.

Preferred nickel(olefin)_(a) complexes, where a=1, 2, 3 or 4, which arecommercially available from Aldrich are Ni(C₂H₄)₃,Ni(1,5-cyclooctadiene)₂ “Ni(COD)₂”, Ni(1,6-cyclodecadiene)₂ orNi(1,5,9-all-trans-cyclododecatriene)₂. Particular preference is givento Ni(COD)₂.

Particularly useful activators are mixed ethylene/1,3-dicarbonylcomplexes of rhodium, for example, bis(ethylene)rhodium acetylacetonateRh(acac)(CH₂═CH₂)₂, bis(ethylene)rhodium benzoylacetonateRh(C₆H₅—CO—CH—CO—CH₃)(CH₂═CH₂)₂ or Rh(C₆H₅—CO—CH—CO—C₆H₅)(CH₂═CH₂)₂.Rh(acac)(CH₂═CH₂)₂ is most suitable. This compound can be synthesized asdescribed by R. Cramer in Inorg. Synth. 1974, 15, 14.

Some amino acid complexes of the formula I can be activated by means ofethylene. The ease of the activation reaction depends critically on thenature of the ligand L¹.

The chosen amino acid complex of the formula I and the activatortogether form a catalyst system.

The activity of the catalyst system of the present invention can beincreased by addition of further aluminum alkyl of the formulaAl(R^(m))₃ or aluminoxanes, particularly when compounds of the formulaIIa or IIb or the abovementioned aluminum or boron compounds bearingelectron-withdrawing radicals are used as activators; aluminum alkyls ofthe formula Al(R^(m))₃ or aluminoxanes can also act as molar massregulators. A further effective molar mass regulator is hydrogen. Themolar mass can be regulated particularly well via the reactiontemperature and the pressure. If the use of a boron compound asdescribed above is desired, the addition of an aluminum alkyl of theformula Al(R^(m))₃ is particularly preferred.

It has been found that the novel amino acid complexes of the formula Iare suitable for polymerizing and copolymerizing olefins. Theypolymerize and copolymerize ethylene and propylene particularly well.

Pressure and temperature conditions during the polymerization can bechosen within wide limits. Pressures in a range from 0.5 bar to 4000 barhave been found to be suitable; preference is given to from 10 to 75 baror high-pressure conditions from 500 to 2500 bar. As regards thetemperature, a range from 0 to 120° C. has been found to be useful;preference is given to from 40 to 100° C., particularly preferably from50 to 85° C.

Suitable monomers are the following olefins: ethylene, propylene,1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene or 1-undecene, withparticular preference being given to ethylene.

Suitable comonomers are α-olefins, for example from 0.1 to 20 mol % of1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or1-undecene. Further suitable comonomers are isobutene, styrene andnorbornene.

Solvents which have been found to be useful are toluene, ortho-xylene,meta-xylene, para-xylene, ethylbenzene and mixtures of these, also,under high-pressure conditions, supercritical ethylene.

If the use of aluminum alkyl or lithium alkyl as scavenger alkyl provesto be useful, it is advantageous to introduce the aluminum alkyl orlithium alkyl as a solution in a hydrocarbon separately from thecatalyst system. However, it is also possible to introduce the scavengeralkyl together with the novel amino acid complexes of the formula I.

The catalyst systems of the present invention have also been found to behydrogen-regulatable, i.e. the molecular weight of the polymersobtainable by means of the catalyst systems of the present invention canbe reduced by addition of hydrogen. If sufficient hydrogen is added,waxes are obtained. The hydrogen concentration required also depends onthe type of polymerization plant used. Thus, polyethylene waxes having amolecular weight M_(w)of at most 20 000 g, preferably at most 10 000 gand particularly preferably at most 7500 g, can be prepared by means ofaddition of hydrogen when using the complexes of the present invention.

The novel amino acid complexes of the formula I can also be usedtogether with metallocenes for the catalysis of olefin polymerization.For this purpose, they can be activated together with or separately fromthe metallocenes and can also be introduced into the reactor eithertogether or separately.

If the novel amino acid complexes of the formula I are to be used inpolymerization processes such as suspension processes, bulkpolymerization processes or gas-phase processes, it is necessary forthem to be immobilized on a solid support. Otherwise, polymer morphologyproblems (lumps, wall deposits, blockages in lines or heat exchangers)can result and force shutdown of the plant. Such an immobilized aminoacid complex of the formula I is referred to as catalyst. Preferredcatalysts comprise one or more amino acid complexes together with anactivator immobilized on a support material.

It has been found that amino acid complexes of the formula I can readilybe deposited on a solid support. Possible support materials are, forexample, porous metal oxides of metals of groups 2-14 or mixturesthereof, also sheet silicates and zeolites. Preferred examples of metaloxides of groups 2-14 are SiO₂, B₂O₃, Al₂O₃, MgO, CaO and ZnO. Preferredsheet silicates are montmorillonites or bentonites; the preferredzeolite is MCM-41.

Particularly preferred support materials are spherical silica gels andaluminosilicate gels of the formula SiO₂.a Al₂O₃, where a is generallyin the range from 0 to 2, preferably from 0 to 0.5. Such silica gels arecommercially available, e.g. Silica Gel SG 332, Sylopol® 948 or 952 or S2101 from W. R. Grace or ES 70X from Crosfield.

As particle size of the support material, mean particle diameters offrom 1 to 300 μm, preferably from 20 to 80 μm, have been found to beuseful; this particle diameter is determined by known methods such assieve methods. The pore volume of these supports is from 1.0 to 3.0ml/g, preferably from 1.6 to 2.2 ml/g and particularly preferably from1.7 to 1.9 ml/g. The BET surface area is from 200 to 750 m²/g,preferably from 250 to 400 m²/g.

To remove impurities, in particular moisture, adhering to the supportmaterial, the support materials can be baked before doping, withtemperatures of from 45 to 1000° C. being useful. Temperatures of from100 to 750° C. are particularly suitable for silica gels and other metaloxides. This baking should be carried out for a period of from 0.5 to 24hours, preferably from 1 to 12hours. The pressure conditions depend onthe method chosen; baking can be carried out in a fixed bed, a stirredvessel or else in a fluidized bed. Baking can quite generally be carriedout at atmospheric pressure. However, reduced pressures of from 0.1 to500 mbar are advantageous; a range from 1 to 100 mbar is particularlyadvantageous and a range from 2 to 20 mbar is very particularlyadvantageous. For fluidized-bed methods, on the other hand, it isadvisable to operate at slightly superatmospheric pressure in a rangefrom >1 bar to 5 bar, preferably from 1.1 to 1.5 bar.

Chemical pretreatment of the support material with an alkyl compoundsuch as an aluminum alkyl Al(R^(m))₃, a lithium alkyl LiR^(k)or analuminoxane of the formula IIa or IIb is also possible.

In the case of a suspension polymerization, use is made of suspensionmedia in which the desired polymer is insoluble or only slightlysoluble, since otherwise deposits of the product are formed on parts ofthe plant in which the product is separated from the suspension mediumand force repeated shutdowns and cleaning operations. Examples ofsuitable suspension media are saturated hydrocarbons such as propane,n-butane, isobutane, n-pentane, isopentane, n-hexane, isohexane andcyclohexane, with preference being given to isobutane.

Pressure and temperature conditions during the polymerization can bechosen within wide limits. A pressure in the range from 0.5bar to 150bar has been found to be useful; preference is given to from 10 to 75bar. A temperature in the range from 0 to 120° C. has been found to beuseful; preference is given to from 40 to 100° C., particularlypreferably from 50 to 85° C.

Suitable monomers are the following olefins: ethylene, propylene,1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene and 1-undecene.

Suitable comonomers are α-olefins for example from 0.1 to 20 mol % of1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or1-undecene. Other suitable comonomers are isobutene, styrene andnorbornene.

Furthermore, the catalysts of the present invention have been found tobe hydrogen-regulatable, i.e. the molecular weight of the polymersobtainable by means of the catalysts of the present invention can bereduced by addition of hydrogen. If sufficient hydrogen is added, waxesare obtained. The hydrogen concentration required also depends on thetype of polymerization plant used. It is also found that the activity ofthe catalysts of the present invention increases when hydrogen is added.

The catalysts of the present invention can also be used together withone or more other polymerization catalysts known per se. Thus, they canbe used together with

-   -   Ziegler-Natta catalysts,    -   supported metallocene catalysts comprising transition metals of        groups 4 to 6 of the Periodic Table of the Elements,    -   catalysts comprising late transition metals (WO 96/23010),    -   Fe or Co complexes with pyridyldiimine ligands, as are disclosed        in WO 98/27124, or    -   chromium oxide catalysts of the Phillips type.

It is possible either to mix various catalysts with one another andintroduce them into the polymerization vessel together or to usecosupported complexes on a single support or else to introduce variouscatalysts separately into the polymerization vessel at the same point orat different points.

The polymerization process of the present invention gives polymers,preferably polyethylene, having high molar masses and a low number ofbranches. The polyethylene obtainable by the process of the presentinvention is particularly suitable for films.

It has also been found that the novel amino acid complexes of theformula I, in particular those in which M=Ni, are particularly suitablefor the polymerization or copolymerization of 1-olefins, preferablyethylene, in emulsion polymerization processes.

Apart from other 1-olefins as comonomers, for example propene, 1-butene,1-hexene, 1-octene, 1-decene, styrene, norbornene or isobutene, thecatalyst system of the present invention also allows the incorporationof polar comonomers, which can be used in amounts of from 0.1 to 50 mol%. Preference is given to

-   -   acrylates such as acrylic acid, methyl acrylate, ethyl acrylate,        2-ethylhexyl acrylate, n-butyl acrylate or tert-butyl acrylate;    -   methacrylic acid, methyl methacrylate, ethyl methacrylate,        n-butyl methacrylate or tert-butyl methacrylate;    -   vinyl carboxylates, particularly preferably vinyl acetate;    -   unsaturated dicarboxylic acids, particularly preferably maleic        acid,    -   unsaturated dicarboxylic acid derivatives, particularly        preferably maleic anhydride and alkylimides of maleic acid, e.g.        N-methylmaleimide.

Furthermore, terpolymers comprising at least 2 of the abovementionedmonomers and ethylene can be prepared.

The emulsion polymerization of 1-olefins using the novel amino acidcomplexes of the formula I can be carried out in a manner known per se.

Here, the order of addition of the reagents in the polymerization is notcritical. Thus, the solvent can firstly be pressurized with gaseousmonomer or liquid monomer can be metered in, after which the catalystsystem is added. However, it is also possible firstly to dilute thesolution of the catalyst system with further solvent and subsequently toadd the monomer.

The actual polymerization is usually carried out at a minimum pressureof 1 bar; below this pressure the polymerization rate is too low.Preference is given to 2 bar and particular preference is given to aminimum pressure of 10 bar.

The maximum pressure is about 4000 bar; at higher pressures, the demandsmade of the material of construction of the polymerization reactor arevery high and the process becomes uneconomical. Preference is given to100 bar, particularly preferably 50 bar.

The polymerization temperature can be varied within a wide range. Theminimum temperature is about 10° C., since the polymerization ratedecreases at low temperatures. Preference is given to a minimumtemperature of 40° C., particularly preferably 65° C. The maximumsensible temperature is 350° C., preferably 150° C., particularlypreferably 100° C.

Prior to the polymerization, the amino acid complex of the formula I isdissolved in an organic solvent or in water. The solution is stirred orshaken for a number of minutes to ensure that it is clear. The stirringtime can be, depending on the solubility of the substance concerned,from 1 to 100 minutes.

At the same time, the activator, if one is necessary, is dissolved in asecond portion of the same solvent or in acetone.

Suitable organic solvents are aromatic solvents such as benzene,toluene, ethylbenzene, ortho-xylene, meta-xylene and para-xylene andalso mixtures thereof. Further suitable solvents are cyclic ethers suchas tetrahydrofuran and dioxane or noncyclic ethers such as diethylether, di-n-butyl ether, diisopropyl ether or 1,2-dimethoxyethane.Ketones such as acetone, methyl ethyl ketone or diisobutyl ketone arealso suitable, as are amides such as dimethylformamide ordimethylacetamide. It is also possible to use mixtures of these solventswith one another or mixtures of these solvents with water or alcoholssuch as methanol or ethanol.

Preference is given to using acetone or water or mixtures of acetone andwater, with any mixing ratio being able to be employed. The amount ofsolvent is likewise not critical, but it should be ensured that theamino acid complex and the activator can dissolve completely, otherwisedecreases in activity may be expected. The dissolution process can, ifdesired, be accelerated by ultrasound treatment.

Any emulsifier to be added can be dissolved in a third portion of thesolvent or can be dissolved together with the complex.

The amount of emulsifier is selected so that the mass ratio of monomerto emulsifier is greater than 1, preferably greater than 10 andparticularly preferably greater than 20. The less emulsifier that has tobe used, the better. The activity in the polymerization is significantlyincreased if an emulsifier is added. This emulsifier can be nonionic orionic in nature.

Nonionic emulsifiers which can be used are, for example, ethoxylatedmonoalkylphenols, dialkylphenols and trialkylphenols, (number of EOunits: 3 to 50, alkyl radical: C₄-C₁₂) and ethoxylated fatty alcohols(number of EO units: 3 to 80; alkyl radical: C₈-C₃₆). Examples are theLutensol® grades from BASF AG or the Triton® grades from Union Carbide.

Customary anionic emulsifiers are, for example, alkali metal salts andammonium salts of alkyl sulfates (alkyl radical: C₈ to C₁₂), of sulfuricmonoesters of ethoxylated alkanols (number of EO units: 4 to 30, alkylradical: C₁₂-C₁₈) and ethoxylated alkyl phenols (number of EO units: 3to 50, alkyl radical: C₄-C₁₂), of alkylsulfonic acids (alkyl radical:C₁₂-C₁₈) and of alkylarylsulfonic acids (alkyl radical: C₉-C₁₈).

Suitable cationic emulsifiers are in general primary, secondary,tertiary or quaternary ammonium salts, alkanolammonium salts, pyridiniumsalts, imidazolinium salts, oxazolinium salts, morpholinium salts,thiazolinium salts bearing a C₆-C₁₈-alkyl, -aralkyl or heterocyclicradical and also salts of amine oxides, quinolinium salts,isoquinolinium salts, tropylium salts, sulfonium salts and phosphoniumsalts. Examples which may be mentioned are dodecylammonium acetate orthe corresponding hydrochloride, the chlorides or acetates of thevarious 2-(N,N,N-trimethylammonium)ethylparaffinic esters,N-cetylpyridinium chloride, N-laurylpyridinium sulfate andN-cetyl-N,N,N-trimethylammonium bromide,N-dodecyl-N,N,N-trimethylammonium bromide,N,N-distearyl-N,N-dimethylammonium chloride and the gemini surfactantN,N′-(lauryldimethyl)ethylenediamine dibromide. Numerous furtherexamples may be found in H. Stache, Tensid-Taschenbuch,Carl-Hanser-Verlag, Munich, Vienna, 1981 and in McCutcheon's,Emulsifiers & Detergents, MC Publishing Company, Glen Rock, 1989.

The components, namely amino acid complex in solution, if desired thesolution of an emulsifier and if desired the solution of an activator,are subsequently introduced into the polymerization reactor. Suitablepolymerization reactors have been found to be stirred vessels andautoclaves and also tube reactors, with the latter being able to beconfigured as loop reactors.

The monomer or monomers to be polymerized is/are mixed with thepolymerization medium. Polymerization media which can be used are wateror mixtures of water with the abovementioned solvents. It has to beensured that the proportion of water is at least 50% by volume, based onthe total mixture., preferably at least 90% by volume and particularlypreferably at least 95% by volume.

The solutions of the amino acid complex, if desired an activator and ifdesired an emulsifier are combined with the mixture of monomer andaqueous polymerization medium. The order of addition of the variouscomponents is not critical per se. However, it is necessary that thecomponents are combined sufficiently quickly for no crystallization ofany sparingly soluble complexes formed as intermediates to occur.

The process of the present invention gives polyolefins and olefincopolymers in high yields, i.e. the activity of the amino acid complexesof the present invention is very high under the conditions of emulsionpolymerization.

As polymerization processes, it is in principle possible to employcontinuous and batchwise processes. Preference is given tosemicontinuous (semibatch) processes in which all components are mixedand further monomer or monomer mixtures is/are then metered in duringthe course of the polymerization.

The process of the present invention initially gives aqueous polymerdispersions.

The mean particle diameters of the polymer particles in the dispersionsobtained according to the present invention are from 10 to 1000 nm,preferably from 50 to 500 nm and particularly preferably from 70 to 350nm. The particle diameter distribution does not, however, have to bevery uniform. For some applications, particularly for those in whichhigh solids contents (>55%) are employed, broad or bimodal distributionsare even preferred.

The polymers obtained by the process of the present invention haveindustrially interesting properties. In the case of polyethylene, theyhave a high degree of crystallinity, which can be determined, forexample, by the number of branches. Less than 100 branches, preferablyless than 50 branches, per 1000 carbon atoms of the polymer are found bymeans of ¹H-NMR and ¹³C-NMR spectroscopy.

The melting enthalpies of the polyethylenes obtainable by the process ofthe present invention are greater than 100 J/g, preferably greater than140 J/g and particularly preferably greater than 180 J/g, measured byDSC.

The molecular weight distributions of the polyethylenes obtainable bythe process of the present invention are narrow, i.e. the Q values arein the range from 1.1 to 3.5, preferably from 1.5 to 3.1.

Advantages of the dispersions obtained according to the presentinvention are the favorable price due to the cheap monomers and processand the fact that they are more stable to weathering than aredispersions of polybutadiene or butadiene copolymers. Compared todispersions of polymers comprising acrylates or methacrylates as mainmonomer, the low tendency to saponification is advantageous. A furtheradvantage is that most monomers are volatile and residual, unpolymerizedmonomers can easily be removed. A final advantage is that no molar massregulators such as tert-dodecyl mercaptan, which are firstly difficultto separate off and secondly have an unpleasant odor, have to be addedduring the polymerization.

The polymer particles can be obtained as such from the initiallyobtained aqueous dispersions by removal of the water and any organicsolvent(s). Numerous customary methods are suitable for removing thewater and any organic solvent(s), for example filtration, spray dryingor evaporation. The polymers obtained in this way have a good morphologyand a high bulk density.

The particle diameters can be determined by light scattering methods. Anoverview may be found in D. Distler “Wäβrige Polymerdispersionen”,Wiley-VCH Verlag, 1st Edition, 1999, chapter 4.

The dispersions obtained according to the present invention can be usedadvantageously in numerous applications, for example paper applicationssuch as paper coating or surface sizing, also paints and varnishes,building chemicals, adhesives raw materials, molded foams, textile andleather applications, carpet backing, mattresses or pharmaceuticalapplications.

EXAMPLE

General Preliminary Remarks

Abbreviations used: IR spectra: m: medium, s: sharp; NMR spectra:s—singlet, m: multiplet,

o-Tol: ortho-tolyl, Ar: aryl, PE: polyethylene, ^(t)Bu tert-butyl, THF:tetrahydrofuran, TEA: triethyl aluminum

All solvents were dried by standard methods as described, for example,in Organikum, VEB Deutscher Verlag der Wissenschaften, Berlin 1984.

All reactions and purification operations were, unless otherwiseindicated, carried out in the absence of air and moisture. The term“ether” always refers to diethyl ether; “pentane” always refers ton-pentane.

The polymer viscosity was determined in accordance with ISO 1628-3. Themolar masses were determined by means of GPC. For the GPC analyses, thefollowing conditions based on DIN 55672 were selected: solvent:1,2,4-trichlorobenzene, flow: 1 ml/min, temperature: 140° C.,calibration: PE standards, instrument: Waters 150 C. The number ofmethyl groups was determined by means of IR spectroscopy.

1. Synthesis of Trans-[Ni(o-Tol)Br(PPh₃)₂]

The compound trans-[Ni(o-Tol)Br(PPh₃)₂] was prepared by a slightlymodified version of the method of S. Y. Desjardins et al., J. Organomet.Chem. 1996, 515, 233.

1.88 g (2.87 mmol) of Ni(PPh₃)₂Cl₂ (commercially available from ABCRGmbH & Co. KG, Karlsruhe) and 1.12 g (17.22 mmol) of Zn powder which hadpreviously been washed with a saturated aqueous NH₄Cl solution and thendried at 110° C. were placed in a 100 ml Schlenk flask. 25 ml of THF and0.69 ml (5.74 mmol) of 2-bromotoluene were subsequently added thereto.The suspension was stirred by means of a precision glass stirrer in anultrasonic bath for about 35 minutes at 35° C. During this time, theinitially greenish black suspension became reddish brown. The residuewas subsequently separated off by filtration through Celite® and thefiltrate was admixed with about 40 ml of methanol. After a number ofhours at −32° C., the product had crystallized out. It was washed withcold methanol.

IR spectrum, ¹H-NMR spectrum and elemental analysis agreed with theliterature data. Further purification was not necessary.

2. Synthesis of the Complexes of the Present Invention

2.1. Synthesis of [Ni(NH₂CH₂CO₂)(o-Tol)(PPh₃)]

226.2 mg (0.3 mmol) of trans-[Ni(o-Tol)Br(PPh₃)₂] were dissolved in 20ml of THF at room temperature and placed in a Schlenk tube. 22.5 mg (0.3mmol) of glycine together with 10 ml of methanol were placed in aseparate vessel and deprotonated by addition of an equimolar amount ofsodium methoxide solution. The suspension obtained in this way wasintroduced while stirring into the Schlenk tube. After addition of onlyabout half the suspension, the contents of the Schlenk tube became lightyellow. The mixture was stirred for a further 2-3 hours at roomtemperature and the reaction mixture became turbid due to precipitationof NaBr. The precipitate was separated off by centrifugation and thesolution was evaporated under reduced pressure. The orange viscousresidue which remained was admixed with about 15 ml of diethyl ether andthe resulting suspension was stirred for 40 minutes in order to separateoff the triphenylphosphine split off in the reaction. The product, whichis very sparingly soluble in ether, was centrifuged off and subsequentlywashed with pentane.

IR (KBr): v (cm⁻¹) 3332 m, 3282 m (NH), 1634 s (COO), 1609 s (NH).

¹H-NMR (270 MHz, CD₃OD): δ 2.59 (s, 3H, CH₃—Ar), 3.19 (m, 2H, NH₂), 3.36(m, 2H, CH₂NH₂), 6.25-6.28 (m, 4H, aromatic o-Tol.-H), 7.17-7.71 (m,15H, PPh₃).

³¹P-NMR (109.4 MHz, CD₃OD): δ 28.36 (s, PPh₃).

2.2. Synthesis of [Ni(NH₂CHC(CH₃)₃CO₂)(o-Tol)(PPh₃)]

350.0 mg (0.46 mmol) of trans-[Ni(o-Tol)Br(PPh₃)₂] were dissolved in 20ml of THF at room temperature and placed in a Schlenk tube. 60.3 mg(0.46 mmol) of L-tert-leucine together with 20 ml of methanol wereplaced in a separate vessel and deprotonated by addition of an equimolaramount of sodium methoxide solution. The suspension obtained in this waywas introduced while stirring into the Schlenk tube. After addition ofonly about 80% by volume of the suspension, the contents of the Schlenktube became light yellow. The turbidity which occurred as a result ofprecipitation of NaBr disappeared again on addition of the remainingsodium methoxide. The mixture was stirred for another 3-4 hours at roomtemperature. The solution was evaporated under reduced pressure. Theyellow-orange viscous residue which remained was admixed with about 15ml of diethyl ether and the resulting suspension was stirred for 40minutes. The NaBr formed during the reaction was separated off bycentrifugation and the product, which was readily soluble in ether, wassubsequently isolated as follows: the ether was distilled off underreduced pressure and the light-yellow residue was washed with hexane.This gave the product in analytically pure form. Separation of the N,Pisomers was dispensed with.

Although the washings contained some product, no work-up of the washingswas carried out.

IR (KBr): v (cm⁻¹) 3435 m (NH), 1637 s (COO), 1601 s (NH).

¹H-NMR (270 MHz, CD₃OD): δ 1.27 (s, 9H, ^(t)Bu), 2.47 (s, CH₃—Ar), 2.59(s, CH₃—Ar), 2.98 (s, 1H, CH), 6.35-6.62 (m, 4H, aromatic o-Tol.-H),7.22-7.73 (m, 15H, PPh₃).

³¹P-NMR (109.4 MHz, CD₃OD): δ 28.09 (s, PPh₃), 28.86 (s, PPh₃).

3. Polymerization Examples

60 mg (0.53 mmol) of triethylaluminum (as 2 molar solution in n-heptane,from Witco) and 400 ml of isobutane were placed in a 1 l autoclave.After the autoclave had been pressurized with ethylene to a pressure of40 bar and had been heated to the temperature indicated in Table 1, theappropriate amount of amino acid complex was in each case added via alock. After 60 minutes, the polymerizations were stopped by venting.

Data on the polymerization conditions and the product properties may befound in Table 1.

TABLE 1 Polymerization results [Ni (NH₂CH₂CO₂) (o-Tol) (PPh₃)] ComplexCocat. h M_(v) Activity IR-spectroscopic end group analysis [mg] TEA PET_(poly) H₂ [dl/ [g/ kg of PE/ trans- Vinyli- Total No. (μmol) [mg] [g][° C.] [l] g] mol] (mol of Ni · h) CH═CH—CH₃ Vinyl dene CH₃ 1 20 (41) 606 100 — 9.58 900000 1756 0.20 0.20 0.05 1.80 2 23 (47) 60 3 50 — 7.97700000 766 0.19 0.69 0.11 1.40 3 16 (33) 60 5 100 — 1 550000 1818 0.220.38 0.13 3.30 η: Staudinger index

1. An amino acid complex of the formula I,

where the variables are defined as follows: M is selected from the groupconsisting of Fe, Co, Ni, Pd, Pt and Ir, X is selected from the groupconsisting of O and S; R¹ to R³ are identical or different and are eachselected from the group consisting of hydrogen, substituted orunsubstituted C₁-C₈-alkyl, substituted or unsubstitutedC₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl which is unsubstituted orsubstituted by at least one identical or different substituent selectedfrom the group consisting of C₁-C₈-alkyl, substituted or unsubstituted,C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy,C₆-C₁₄-aryloxy, SiR⁴R⁵R⁶ and O—SiR⁴R⁵R⁶, where R^(4-R) ⁶ are selectedfrom the group consisting of C_(1-C) ₈-alkyl, C₃-C₁₂-cycloalkyl,C₇-C₁₃-aralkyl and C₆-C₁₄-aryl; five- to six-memberednitrogen-containing heteroaryl radicals Y, unsubstituted or substitutedby at least one identical or different substituent selected from thegroup consisting of substituted or unsubstituted C₁-C₈-alkyl,C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy,C₆-C₁₄-aryloxy, SiR⁴R⁵R⁶ and O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected fromthe group consisting of C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyland C₆-C₁₄-aryl; and CH₂—Y, where R¹ and R² optionally are joined to oneanother to form a 5- to 10-membered ring; y is an integer from 0 to 4;L¹ is an uncharged, inorganic or organic ligand selected from the groupconsisting of phosphines (R⁷)_(x)PH_(3−x), amines (R⁷)_(x)NH_(3−x),ethers (R⁷)₂O, H₂O, alcohols (R⁷)OH, pyridine, pyridine derivatives ofthe formula C₅H_(5−x)(R⁷)_(x)N, CO, C₁-C₁₂-alkyl nitriles andC₆-C₁₄-aryl nitriles, where x is an integer from 0 to 3; L² is aninorganic or organic anionic ligand, where L¹ and L² optionally arejoined to one another by one or more covalent bonds, and is selectedfrom the group consisting of halide ions, amide anions (R⁷)_(h)NH_(2−h),where h is an integer from 0 to 2, C₁-C₆-alkyl anions, the allyl andmethallyl anions, the benzyl anion and C₆-C₁₄-aryl anions; R⁷ areidentical or different and are selected from the group consisting ofhydrogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and substitutedor unsubstituted C₆-C₁₄-aryl; z is an integer ranging from 1 to
 3. 2.The amino acid complex of formula I as claimed in claim 1, wherein M isselected from the group consisting of Ni and Pd, X is O, y is 0; and zis1.
 3. The amino acid complex of formula I as claimed in claim 1,wherein M is Ni, L¹ are phosphines (R⁷)_(x)PH_(3−x), where x=0, 1, 2 or3, L² is a benzyl or aryl anion; R¹ is hydrogen, R⁷ are identical ordifferent and are selected from the group consisting of hydrogenhydrogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and substitutedor unsubstituted C₆-C₁₄-aryl.
 4. An amino acid complex of the formula I,

where the variables are defined as follows: M is Ni, X is selected fromthe group consisting of O and S; R¹ to R³ are identical or different andare each selected from the group consisting of hydrogen, substituted orunsubstituted C₁-C₈-alkyl, substituted or unsubstitutedC₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl which is unsubstituted orsubstituted by at least one identical or different substituent selectedfrom the group consisting of substituted or unsubstituted C₁-C₈-alkyl,C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxyand C₆-C₁₄-aryloxy, SiR⁴R⁵R⁶ and O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selectedfrom the group consisting of C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl,C₇-C₁₃-aralkyl and C₆-C₁₄-aryl; five- to six-memberednitrogen-containing heteroaryl radicals Y, unsubstituted or substitutedby at least one identical or different substituent selected from thegroup consisting of substituted or unsubstituted C₁-C₈-alkyl,C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy,C₆-C₁₄-aryloxy, SiR⁴R⁵R⁶and O—SiR⁴R⁵R⁶, where R⁴-R⁶ are selected fromthe group consisting of C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyland C₆-C₁₄-aryl; and CH₂—Y, where R¹ and R² optionally are joined to oneanother to form a 5- to 10-membered ring; y is an integer from 0 to 4;L¹ is an uncharged, inorganic or organic ligand; L² is an inorganic ororganic anionic ligand, where L¹ and L² optionally are joined to oneanother by one or more covalent bonds; z is an integer ranging from 0 to3.
 5. A process for preparing amino acid complexes as claimed in claim1, which comprises: deprotonating an amino acid of formula II

and subsequently reacting the product with a metal compound of theformula M(L¹)₂₊₁L²X¹, where X¹ is selected from the group consisting ofhalides and alkoxides and the other variables are as defined above. 6.The process as claimed in claim 5, wherein the amino acid isdeprotonated with a base selected from the group consisting of lithiumdiisopropylamide, alkyllithium compounds and alkoxides.
 7. The processas claimed in claim 5, wherein the deprotonation is conducted at atemperature of −20° C. to 80° C.
 8. A process for preparing a supportedcatalyst for the polymerization or copolymerization of olefins, whichcomprises: depositing at least one amino acid complex as claimed inclaim 1 and, optionally, an activator on a solid support.
 9. The processas claimed in claim 8, wherein the solid support is a porous metal oxideof a metal selected from the group consisting of metals of Groups 2-14,sheet silicates and zeolites.
 10. The process as claimed in claim 8,wherein the solid support has a mean particle diameter ranging from 1 to300 μm and a pore volume ranging from 1.0 to 3.0 ml/g.
 11. A supportedcatalyst for the polymerization or copolymerization of olefins,comprising: at least one amino acid complex of formula I of claim 1, asolid support material and, optionally, an activator.
 12. The supportedcatalyst as claimed in claim 11, wherein the activator is an aluminumalkyl, an aluminoxane or a boron compound that contains anelectron-withdrawing group.
 13. A process for the polymerization orcopolymerization of olefins, which comprises: (co)polymerizing at leastone monomer olefin in the presence of amino acid complex as claimed inclaim
 1. 14. The process as claimed in claim 13, wherein said olefin isethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-deceneor 1-undecene.
 15. The process as claimed in claim 13, wherein the(co)polymerization is conducted in the presence of from 0.1 to 20 mol %of a comonomer that is isobutene, styrene, norbomene, 1-butene,1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or1-undecene.
 16. The process as claimed in claim 15, wherein the(co)polymerization is conducted in the presence of the supportedcatalyst as claimed in claim
 11. 17. The process as claimed in claim 15,wherein the (co)polymerization is conducted as an emulsionpolymerization process or an emulsion copolymerization process.